AEMCA Practice Exam

What is a characteristic of Mobitz Type 1 rhythm?

1. Consistent heart rate

2. Dropping of every other beat

3. Gradual lengthening of the PR interval until a dropped beat occurs

4. No dropped beats

The correct answer is: Gradual lengthening of the PR interval until a dropped beat occurs

Mobitz Type 1, also known as Wenckebach, is characterized by a progressive lengthening of the PR interval on consecutive beats until a QRS complex is dropped. This phenomenon occurs as the conduction through the AV node becomes increasingly delayed, resulting in the eventual failure to conduct the impulse to the ventricles, leading to the dropped beat. This pattern of gradual prolongation followed by a drop is distinctive and aids in the differentiation from other types of heart block. In contrast, consistent heart rates are associated with stable rhythms, while dropped beats occurring in every other beat might align more with Mobitz Type 2 or a different type of block. The absence of dropped beats indicates normal conduction and rhythm, which would not be seen in Mobitz Type 1. Understanding these characteristics is essential for recognizing and diagnosing types of heart rhythms effectively.